This invention relates to a baler for producing cylindrical ("round") bales comprising a plurality of endless belts for forming an adjustable bale forming chamber and more particularly relates to guide rollers used to support such belts.
Prior art balers of the foregoing type are comprised generally of a plurality of side-by-side, longitudinally extending belts supported on a plurality of transverse rollers. An expandable bale forming chamber is defined by the sides of the balers, the rollers and the belts. A long standing problem encountered in the use of such balers is caused by crop material becoming entrapped within volumes contiguous with the bale forming chamber and substantially enclosed by the sides of the baler, the rollers and the belts. The crop enters these volumes from the bale forming chamber by passing through spaces between longitudinally adjacent belts. When the crops become entrapped within these volumes, it tends to wrap around the rollers which is detrimental to proper belt tracking on the rollers and tends to retard enlargement of the bale forming chamber as the bale grows in diameter. Eventually, if uncorrected, the belts become bound (or may even break) and bale formation is no longer possible until the wrapped and entrapped hay is removed.
Also, crop material has a tendency to become entwined around belt guide rollers which engage the belts at locations in contact with the bale during formation. The crop material in the chamber extends through gaps between longitudinally adjacent belts and can become wedged into a pinch point formed between a belt and the roller. Because the belt and the roller are driven, the interaction thereof with the crop tends to wrap the crop material around the roller. The wrapping of the roller can lead to poor belt tracking, the binding of the belts and even belt breakage.
A number of solutions to mitigate the effect of these problems have been proposed. For example, U.S. Pat. No. 3,125,948 discloses a cylindrical baler with a cleaner bar located parallel to and in a closely spaced relationship to an upper drive roller to prevent the wrapping of the drive roller with crop material. U.S. Pat. No. 4,182,101 discloses a cylindrical baler with a bale positioning roller located parallel to and closely adjacent a belt guide roller which is normally subject to wrapping problems. The bale positioning roller prevents the bale from resting on the belt guide roller and forming a pinch point between the belt and the belt guide roller, the formation of which is said to be conducive to roller wrapping. In addition, the bale positioning roller has a plurality of projections which extend between adjacent belts and pull crop material away from the belt guide roller to minimize wrapping. The latter design has been found to have the disadvantage of producing a bale with a ragged exterior surface because the bale rides on the bale positioning roller which has a plurality of projections.